1. Field of the Invention
The present invention relates to a method of, and a device for enhancing an image that obtains improved quality output when a printer prints a document printed with respect to an image input from an image scanning device. More particularly, the present invention relates to a method of, and a device for enhancing an image that distinguishes an actual edge of a text region from an edge of an image region to emphasize the actual edge of the text region.
2. Description of the Related Art
An image enhancement apparatus operates to ensure that a given image is converted to the extent that a human can easily discern. An example of a general image enhancement apparatus and method thereof is disclosed in Korean Patent No. 10-2002-0059531 (the '531 Korean Patent), the entire contents of which are hereby incorporated by reference, which discloses a method and device for enhancing the quality of a text and image document. The '531 Korean Patent device mainly comprises a classification unit, a post-process unit, an emphasis unit.
The classification unit of the '531 Korean Patent uses saturation, slope information, and the number of connecting element number to estimate pixels to be processed as either ‘T’, ‘I’ and ‘U’ pixels. The post-process unit corrects errors in classified information to determine ‘T’ or ‘I’ pixels. The emphasis unit emphasizes a present pixel from the classified ‘T’ information to obtain an improved image.
The above-described conventional method compares the average values of the mask and brightness value of each pixel from a single window mask to extract a binary value and calculate a connecting element value N. Because the conventional method uses only a single window to calculate a connecting element value N, characteristics around the target pixel can not be fully reflected. Accordingly, edge detection accuracy may be decreased or the requirements for memory and calculation increased, especially for documents that are output based on a low line per inch (LPI) requirement, such as a newspaper having characteristics around the observed pixel similar to a letter.
The conventional method computes the binary data on the basis of average values in a window mask. The number of pixels having the binarization data value of 1 is not regular. Therefore, the possibility of mis-classification increases between a text edge and a halftone image edge, when the edge is configured diagonally.